This invention relates to bowling lane masking units, and particularly to a stabilized masking unit vertical lift.
A bowling facility masking unit is a graphic panel mounted directly in front of all pinsetter mechanisms in a bowling center. It provides an aesthetically pleasing structure blocking the bowler's view of the pinsetter operation mechanism above the pins. A variety of scenes/graphics are available as standard products. Custom graphic development is also offered to customers with special graphic requests. In addition to providing the masking function, a double upper and lower set of masking units can be employed, with the lower panel also serving as a mounting location and visual contrast for the light assembly that displays pins remaining after the first and second bowled ball. A representative masking unit is disclosed in U.S. Pat. No. 4,339,129. Bowling center masking installations usually consist of both upper and lower masking panels. However, in some installations only the lower panel is employed and the upper panel is omitted.
During normal bowling sessions, the upper and lower masking unit panels usually remain in place and provide the masking function described above. However, during periods between bowling sessions, the lanes may be cleaned and oiled. In addition, during bowling sessions, minor repairs or adjustments to the pinsetter may be required. Each of these conditions requires that the lower panel, with optional ball light assemblies, be quickly and easily moved by a single individual to provide ready access. However, the moved lower panel cannot physically block any bowling lane or visually interfere with bowling in adjacent lanes. Thus, the preferred temporary storage position of the lower panel is upward, preferably directly behind the upper panel. A required operating feature is that the lower panel can be easily lifted by a single individual from anywhere along the length of the masking unit, i.e., the extreme left, center, or righthand edge, without binding of the panel. The lower panel must be automatically captured and physically held in place by components of the supportive frame until cleaning or repair is completed.
The functions defined above are currently accomplished with garage door type torsion spring technology. A stiff torsion spring is mounted symmetrically around a horizontally oriented, solid, cylindrical, cross lane, steel bar with sprockets assembled to each end of the bar. The sprockets drive vertically oriented roller link chains located on each end of the masking unit frame. These chains are joined with additional vertical frame members that support the graphic panels. This mechanical system is designed and assembled such that the weight of the graphic panel and its considerable supportive structure can be raised at any point across its width without excessive binding of the assembly. The amount of lifting assistance provided by the torsion spring is determined by the stored energy of the spring, and can be adjusted by changing the number of turns or the "pre load" of the spring. It is a well-known fact that the adjustment of the spring can be difficult if attempted by an untrained and/or inexperienced person. Moreover, the mechanical implementation of the methodology described above requires very substantial mechanical structure to support the numerous mechanical components. The end result is a complex, heavy, and relatively costly assembly to produce, package, install and maintain.